The invention relates to continuous casting of molten metal in general and more particularly to an electromagnetic seal adapted to confine the molten metal within the mold at the inlet of feeding material for the casting vessel.
It is generally known to use electromagnetic forces generated with an electrical coil in order to induce forces in the molten metal of continuous casting apparatus for stirring as well as for levitating the molten metal. Such forces result from the interaction of the magnetic field from the coil and eddy currents induced in the metal.
It is known from U.S. Pat. No. 3,646,988 to apply an annular electromagnetic coil around the pouring and solidification zones of molting metal in order to prevent flowing as well as for shaping solidified metal in a continuous casting process.
It is known from U.S. Pat. No. 3,939,799 to generate electromagnetic forces with an electromagnet in order to prevent molten metal from leaking out at the strip feeding end of a plating tank.
It is known from U.S. Pat. No. 3,735,799 to produce with single phase alternating current an electromagnetic alternating field around the melting column under continuous casting in order to hold together laterally the metal without spreading and without mold walls.
It is known from U.S. Pat. No. 4,450,892 in a horizontal continuous casting installation to provide an electromagnetic coil in a zone of discontinuity in the mold of molten metal, especially where the casting vessel has a nozzle-like connecting portion, in order to generate electromagnetic forces along such connecting portion to accelerate metal flow and maintain a stable meniscus. In such instance, polyphase current is used so as to produce a travelling electromagnetic wave.
It is known from U.S. Pat. No. 4,414,285 to use polyphase currents passing in a plurality of coils to push or pull a column of metal combining molten and solidified metal at the outlet of a casting vessel.